The present invention relates to a double-color ink and a writing utensil using the same.
Double-color inks, when used in writing, are capable of producing a double-color writing (the contour line as shown in FIG. 1(A)) by making an outline around the writing, and used for markers and fiber-tipped pens.
As such double-color inks are known, for example, those which consist of metal powder pigments, water-soluble dyes, water and permeable organic solvents; are used in writing and drawing onto permeable writing surfaces as of paper, fabrics, etc.; produce a contouring effect as the water-soluble dyes permeate and disperse around the writing formed by the metal powder pigments, as shown in FIG. 1(B) (Japanese Unexamined Patent Publications No. 231777/1985, No. 123684/1986).
Thus, the conventional double-color inks utilize a double-color development mechanism shown in FIGS. 1(A) and (B). It is common that two types of the coloring components are used in the double-color inks: the colorant which permeates paper and the like and the colorant which do not permeate, namely a water-soluble dye and a metal powder pigment, respectively.